Energy efficient storage of error-correction-detection information

ABSTRACT

Data and error correction information may involve accessing multiple data channels (e.g., 8) and one error detection and correction channel concurrently. This technique requires a total of N+1 row requests for each access, where N is the number of data channels (e.g., 8 data row accesses and 1 error detection and correction row access equals 9 row accesses.) A single (or at least less than N) data channel row may be accessed concurrently with a single error detection and correction row. This reduces the number of row requests to two (2)—one for the data and one for the error detection and correction information. Because, row requests consume power, reducing the number of row requests is more power efficient.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating a memory system.

FIG. 1B illustrates a first example storage location relationship between data and error detection and correction information.

FIG. 1C illustrates the use of an error detection and correction data cache.

FIG. 1D illustrates a second example storage location relationship between data and error detection and correction information.

FIG. 1E illustrates a third example storage location relationship between data and error detection and correction information.

FIG. 1F illustrates a fourth example storage location relationship between data and error detection and correction information.

FIG. 2 is a flowchart illustrating method of accessing data and error detection and correction information.

FIG. 3 is a flowchart illustrating a method of using cached error detection and correction information.

FIG. 4 is a flowchart illustrating a method of caching and using error detection and correction information.

FIG. 5 is a flowchart illustrating a method of accessing error detection and correction information from an open row.

FIG. 6 is a flowchart illustrating another method of accessing error detection and correction information from an open row.

FIG. 7 is a block diagram of a processing system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following disclosure relates to, among other things, memory components, memory controllers, and/or systems that have features and/or functionality for error detection and correction. A way of accessing data and error correction information involves accessing multiple data channels (e.g., 8) and one error detection and correction channel concurrently. This allows for efficient storage of the data because the same command and address can be used to access both the error detection and correction information channel and the data channels. However, every access using this scheme requires a total of N+1 row requests, where N is the number of data channels (e.g., 8 data row accesses and 1 error detection and correction row access equals 9 row accesses.) In an embodiment, a single (or at least less than N) data channel row is accessed concurrently with a single error detection and correction row. This reduces the number of row requests to two (2)—one for the data and one for the error detection and correction information. Because row requests consume power, reducing the number of row requests is more power efficient.

FIG. 1A is a block diagram illustrating a memory system. In FIGS. 1A-1E, memory system 100 comprises controller 110, memory channels 120 a-120 d, and memory devices 130 a-130 d. Controller 110 includes interfaces 115 a-115 d and control logic 114 a-114 d. Memory device 130 a is operatively coupled to interface 115 a of controller 110 via memory channel 120 a. Memory device 130 b is operatively coupled to interface 115 b of controller 110 via memory channel 120 b. Memory device 130 c is operatively coupled to interface 115 c of controller 110 via memory channel 120 c. Memory device 130 d is operatively coupled to interface 115 d of controller 110 via memory channel 120 d.

Control logic 114 a of controller 110 is operatively coupled to interface 115 a. Control logic 114 b of controller 110 is operatively coupled to interface 115 b. Control logic 114 c of controller 110 is operatively coupled to interface 114 c. Control logic 114 d of controller 110 is operatively coupled to interface 115 d. Each of control logic 114 a-114 d operates the corresponding interface 115 a-115 d. Each of control logic 114 a-114 d can operate independently of each other. Likewise, each of interfaces 115 a-115 d can be operated independently of each other.

Controller 110 and the memory devices 130 a-130 d may be integrated circuit type devices, such as are commonly referred to as a “chips”. Memory devices 130 a-130 d may be standalone devices, or may be one or more components of a memory module. A memory controller, such as controller 110, manages the flow of data going to and from memory devices and/or memory modules. A memory controller can be a separate, standalone chip, or integrated into another chip. For example, a memory controller may be included on a single die with a microprocessor, or included as part of a more complex integrated circuit system such as a block of a system on a chip (SOC). Memory devices 130 a-130 d can include a dynamic random access memory (DRAM) core or other type of memory cores, for example, static random access memory (SRAM) cores, or non-volatile memory cores such as flash. Controller 110 and memory devices 130 a-130 d may be interconnected with each other in a variety of system topologies including on a PC board (e.g., where the memory is on a module and the controller is socketed to the PC board, or in “die-down” arrangement where one or both of the chips are soldered to the PC board), stacked one on top of another and encapsulated in a single package or each having separate package (package-on-package), both disposed on a shared substrate, on an interposer, or even in a direct-attach arrangement.

Controller 110 is operatively coupled to memory devices 130 a-130 d to communicate commands, addresses, and data with memory devices 130 a-130 d. Controller 110 can operate, via memory channels 120 a-120 d, each of memory devices 130 a-130 d independently. In other words, each of control logic 114 a-114 d and interfaces 115 a-115 d operate the command, address, and data transfer functions of their respective memory channel 120 a-120 d independently of the other of memory channels 120 a-120 d.

Controller 110 may be configured to allocate a plurality of memory channels 120 a-120 d and corresponding memory devices 130 a-130 d to store data and error detection and correction information. For example, controller 110 may allocate 8 channels and 8 memory devices (illustrated in FIGS. 1A-1E by 120 a-120 c and 130 a-130 c, respectively) to store data, and a single remaining channel and memory device (illustrated in FIGS. 1A-1E by 120 d and 130 d, respectively) to store error detection and correction information. Controller 110 may access all 9 memory channels 120 a-120 d each time controller 110 performs an access thereby activating 9 rows (i.e., one row in each of 9 memory devices 130 a-130 d.) However, activating 9 rows for every access may be too power inefficient for some applications.

In an embodiment, memory channels 120 a-120 d each include respective memory access interfaces that operate independently of the accesses that occur via the other of the memory channels 120 a-120 d. To be independent, in an embodiment, each of memory channels 120 a-120 d include command, address, and data transfer functions that operate independently of the command, address, and data transfer functions of the other memory channels 120 a-120 d. Controller 110 may be configured to concurrently access two or more of memory channels 120 a-120 d.

Memory channel 120 a may be used to access a first data word group that is stored contiguously in a row of memory device 130 a. Memory channel 120 d may be used by controller 110 as an error detection data channel. Memory channel 120 d may be used by controller 110 to access a first group of check bits associated with the first data word group.

In an embodiment, system 100 and/or controller 110 may include a check bit cache to provide the first group of check bits associated with the first data word group. In response to an access to the first data word group, the check bit cache can provide the first group of check bits (which is associated with the first data word group) without using an access via the error detection data channel 120 d.

Memory channel 120 b may be used to access a second data word group that is stored contiguously in a row of memory device 130 b. In an embodiment, the accessed row of memory device 130 a is accessed using a first row address on data channel 120 a, and the row of memory device 130 b using the same row address, but on data channel 120 b. In an embodiment, this first row address is also the row of memory device 130 d that holds the check bits associated with the first and second data word groups. In an embodiment, the accessed row of memory device 130 a is accessed using a first row address on data channel 120 a, and the row of memory device 130 b using a second, but different, row address. In this case, a third row address into memory device 130 d, different first and second row addresses may hold the check bits associated with both or the first and second data word groups.

In an embodiment, memory channels 120 a-120 d each include respective memory access interfaces that operate independently of the accesses that occur via the other of the memory channels 120 a-120 d. To be independent, in an embodiment, each of memory channels 120 a-120 d include command, address, and data transfer functions that operate independently of the command, address, and data transfer functions of the other memory channels 120 a-120 d. Controller 110 may be configured to concurrently access two or more of memory channels 120 a-120 d. Controller 110 may operate memory channel 120 d as an error detection data channel. Controller 110 may use channel 120 d to access a first group of check bits corresponding to data stored in a single row of memory device 130 a which is accessed via memory channel 120 a. In an embodiment, controller 110 stores this first group of check bits is in a single row of memory device 120 d that is accessed via channel 120 d.

In an embodiment, a second group of check bits may be stored in the single row of memory device 130 d. This second group of check bits are associated with a single row of a memory device 120 b which is accessed via memory channel 120 b. In an embodiment, controller 110 accesses the first group of check bits and the second group of check bits from the single row of the error detection and correction channel memory device 130 d using a single row activate command to access both the first group of check bits and the second group of check bits.

In an embodiment, system 100 includes a check bit data cache. This check bit data cache can provide, without error detection and correction channel memory device 130 d being accessed, the first (and/or second) group of check bits. In an embodiment, this check bit cache is included in controller 110.

In an embodiment, controller 110 accesses channel 120 a to receive a first data word group that is stored contiguously in a first row of memory device 130 a. Concurrently with accessing the first memory channel, controller 110 accesses channel 120 d (which is configured as an error correction data channel) to receive a first set of check bits associated with the first data word group. In an embodiment, before accessing channel 120 d to receive the first set of check bits, controller 110 may determine whether an error detection and correction data cache holds a copy of the first set of check bits.

When controller 110 accesses error correction data channel 120 d concurrently with channel 120 a, controller 110 may also receive a second set of check bits associated with a second data word group. In other words, controller 110 may read more check bit data than is strictly required to check the first data word group. This additional check bit data may correspond to check bit data for data word groups that are stored on different memory devices 130 a-130 c and/or different rows of these devices 130 a-130 c. In this case, controller 110 may cache this extra data in an error detection and correction data cache. If controller 110 later receives a request to access memory channel 120 b to receive a second data word group, and the additional check bit data was stored in the error detection and correction data cache, controller 110 may provide the second set of check bits from the error detection and correction data cache without concurrently accessing the error correction data channel 120 d to receive the second set of check bits.

FIG. 1B illustrates a first example storage location relationship between data and error detection and correction information. FIG. 1B illustrates memory system 101 which is structurally similar to memory system 100, but is configured to store data using the first example storage location relationship between data and error detection and correction data. In FIG. 1B, controller 110 is configured to store the data for a single access request in a single row 133 a-133 b of a single memory device 130 a-130 c. The error detection and correction information for all of the data memory devices 130 a-130 c is stored in a single, dedicated, memory device 130 d.

This is illustrated in FIG. 1B by the data 131 a (a.k.a., data word group) for a first access (e.g., burst) being stored contiguously in row 133 a of memory device 130 a. The data 131 b for a second access is stored contiguously in row 133 b of memory device 130 b. In an embodiment, data 131 a and data 131 b occupy at least one entire row 133 a-133 b. The error detection and correction data 132 a (e.g., check bits) associated with the first access and the error detection and correction data 132 b associated with the second access are both stored in dedicated error detection and correction memory device 130 d. With this configuration, memory device 130 d (and by extension channel 120 d) provides the error detection and correction data for the data in the remaining memory devices 130 a-130 c (and by extension channels 120 a-120 c). In an embodiment, the error detection and correction data stored in memory device 130 d stores the error detection and correction data associated with 8 other memory devices 130 a-130 c. However, because only a single data memory device 130 a-130 c and the single error detection and correction memory device 130 d is accessed per request, at most 2 devices need to activate a row—thereby reducing the power consumption when compared to requests that activate 9 rows (i.e., 1 row per device for all 9 devices).

It should be understood that the ratio of data channels to error detection and correction channels can be selected according to the application and/or expected data traffic pattern. For example, requests to error detection and correction channel 120 d can be for a smaller amount of data than the requests to the data channels. For example, for every 8 bytes requested from data channel 120 a, controller 110 may only request a single byte from error detection and correction data channel 120 d. In another example, the dedicated error detection and correction channel 120 d may hold the error detection and correction data for a smaller number of data channels 120 a-120 c (e.g., error detection and correction channel 120 d holds the error detection and correction data for only 4 data channels 120 a-120 c.) This may result in a less efficient use of the memory on error detection and correction memory device 120 d. However, the number of conflicts resulting from the use of only a single channel for error detection and correction data may be reduced when compared to a data channel to error detection and correction channel ration of 8:1. Conflicts can occur when controller 110 wants to access a data memory channel 120 a-120 c while the error detection and correction channel 120 d is still busy with a previous request. For example, when controller 110 wants to access memory channel 120 b, but error detection and correction channel 120 d is currently busy providing data for an access on data channel 120 a, controller 110 may need to wait until error detection and correction channel 120 d is no longer busy to complete, and check the result with error detection and correction data, controller 110's access to memory channel 120 b.

In an embodiment, the error detection and correction data stored in error detection and correction memory device 130 d can be arranged according to an expected access pattern. For example, if it is expected that controller 110 will make multiple sequential accesses to the same row, but on different memory devices, controller 110 may store all of the error detection and correction data for those rows in the corresponding row of error detection and correction device 130 d. In this manner, the corresponding row in error detection and correction device 130 d only needs to be accessed/activated once by controller 110 to satisfy the error detection and correction data requirements of these accesses.

FIG. 1C illustrates the use of an error detection and correction data cache. FIG. 1C illustrates memory system 102 which is structurally similar to memory system 100, but is configured to use an error detection and correction data cache 111 to reduce access conflicts while accessing error detection and correction data 132 a-132 b stored in error detection and correction data memory device 130 d. Controller 110 may include (or be coupled with) a cache memory 111 to hold error detection and correction data from error detection and correction memory device 130 d. This can reduce the conflicts on error detection and correction channel 120 d by providing recently used error detection and correction data 112 from error detection and correction cache 111 rather than requiring an access to error detection and correction memory device 130 d.

The arrangement/design of error detection and correction cache 111 may be selected according to the application and/or expected data traffic pattern. For example, error detection and correction cache 111 may comprise a single line or row of cached error detection and correction data 112 (from error detection and correction channel 120 d) dedicated to each data channel 120 a-120 c. In another example, the entirety of error detection and correction cache 111 may support caching of error detection and correction data associated with all data channels 120 a-120 c. Error detection and correction cache 111 may, in this case, have a large storage capacity (e.g., 64 kB) and have multiple cache ways (e.g. 4-way set associative cache.)

FIG. 1D illustrates a second example storage location relationship between data and error detection and correction information. FIG. 1D illustrates memory system 103 which is structurally similar to memory system 100, but is configured to store data using the second example storage location relationship between data and error detection and correction data. In FIG. 1D, row 134 a in memory device 130 a and row 134 b in memory device 130 b have the same row addresses. In this example, controller 110 stores the error detection and correction data 132 a associated with data 131 a in row 134 a of memory device 130 a and the error detection and correction data 132 b associated with data 131 b in row 134 b of memory device 130 b in the same row 134 d of error detection and correction memory device 130 d.

FIG. 1E illustrates a third example storage location relationship between data and error detection and correction information. FIG. 1E illustrates memory system 103 which is structurally similar to memory system 100, but is configured to store data using the third example storage location relationship between data and error detection and correction data. In FIG. 1E, row 135 a in memory device 130 a that is storing data 131 a, and row 135 b in memory device 130 b that is storing data 131 b, have different row addresses. However, in this example, controller 110 stores the error detection and correction data 132 a associated with data 131 a and the error detection and correction data 132 b associated with data 131 b in the same row 135 d in error detection and correction memory device 130 d. Controller 110 may store the error detection and correction data 132 a associated with data 131 a and the error detection and correction data 132 b associated with data 132 a in row 135 d according to, for example, a hashing function that is based on, for example, both the row address and a data channel 120 a-120 c address.

FIG. 1F illustrates a fourth example storage location relationship between data and error detection and correction information. FIG. 1F illustrates memory system 103 which is structurally similar to memory system 100, but is configured to store data using the fourth example storage location relationship between data and error detection and correction data. In FIG. 1D, row 136 a in memory device 130 a that is storing data 131 a and row 136 b in memory device 130 b that is storing data 131 b have the same row addresses. In this example, controller 110 stores the error detection and correction data 132 a associated with data 131 a in row 136 e and the error detection and correction data 132 b associated with data 132 a in a different row 136 d of error detection and correction memory device 130 d.

FIG. 2 is a flowchart illustrating method of accessing data and error detection and correction information. The steps illustrated in FIG. 2 may be performed by controller 110 and/or one or more elements of systems 100-105. By a controller, memory devices are accessed that are on a set of memory channels that each include command, address, and data transfer functions that operate independently of the command, address, and data transfer functions of the other channels in the set of memory channels (202). For example, controller 110 may access memory devices 130 a-130 d that are connected respectively to memory channels 120 a-120 d. Memory channels 120 a-120 d each include command, address, and data transfer functions that operate independently of the other of memory channels 120 a-120 d.

By the controller, a first memory channel of the set of memory channels is accessed to receive a first data word group that is stored contiguously in a first row of a first memory device coupled to the memory channel (204). For example, controller 110 may access memory channel 120 a to receive data word group 131 a where data word group 130 a is stored contiguously in row 133 a of memory device 130 a.

By the controller, and concurrently with the accessing of the first memory channel, an error correction data channel is accessed to receive a first set of check bits associated with the first data word group (206). For example, concurrently with accessing channel 120 a to receive data word group 131 a, controller 110 may access error detection and correction channel 120 d to receive error detection and correction data 132 a that is associated with data word group 131 a.

FIG. 3 is a flowchart illustrating a method of using cached error detection and correction information. The steps illustrated in FIG. 3 may be performed by controller 110 and/or one or more elements of systems 100-105. A first memory channel of a plurality of independent memory channels is accessed to receive a first data word group that is stored contiguously in a first row of a first memory device couple to the first memory channel (302). For example, controller 110 may access memory channel 120 b in order to read data word group 131 b from row 133 b of memory device 130 b.

Concurrently with accessing the first memory channel, an error correction data channel is accessed to receive a first set of check bits associated with the first data word group (304). For example, controller 110 may access memory channel 120 d in order to read error detection and correction data 132 b that is associated with data word group 131 b. The error detection and correction data 132 b may be used to detect and/or correct errors in data word group 131 b.

A request to access a second memory channel of the plurality of memory channels to receive a second data word group is received, the second data word group being stored contiguously in a second row of a second memory device coupled to the second memory channel (306). For example, controller 110 may receive a request (e.g., from a processor etc.) directed to reading data word group 131 a from channel 120 a which is stored contiguously in row 133 a of memory device 130 a. In response to this request, controller 110 may access channel 120 a and receive data word group 131 a from memory device 130 a.

In response to the request to access the second data word group, a second set of check bits is provided from an error detection data cache without concurrently accessing the error correction data channel to receive a second set of check bits associated with the second data word group (308). For example, in response to a request to read a data channel 120 a, controller 110 may query error detection and correction cache 111 to determine if a cached copy 112 of error detection and correction data 132 a associated with the request is stored in error detection and correction cache 111. If a cached copy 112 of the error detection and correction data 132 a that is associated with the requested data word group is present in error detection and correction cache 111, controller 110 may forego accessing error detection and correction memory channel 120 d. Instead, controller 110 may retrieve the cached copy 112 of error detection and correction data 132 a (without concurrently accessing error detection and correction data channel 120 d and/or error detection and correction memory device 130 d) and use this copy to detect and/or correct errors in data word group 131 a.

FIG. 4 is a flowchart illustrating a method of caching and using error detection and correction information. The steps illustrated in FIG. 4 may be performed by controller 110 and/or one or more elements of systems 100-105. By a controller, an error correction data channel is accessed to receive a first set of check bits associated with a first data word group (402). For example, controller 110 may access error detection and correction data channel 120 d in order to receive error detection and correction data 132 a from error detection and correction memory device 130 d. Controller 110 may retrieve error detection and correction data 132 a and store a copy 112 in error detection and correction cache 111 in response to a request for the corresponding data word group 131 a.

The first set of check bits are stored in an error correction data cache (404). For example, controller 110 may store a copy 112 of error detection and correction data 132 a in error detection and correction cache 111. Controller 110 may retrieve error detection and correction data 132 a and store a copy 112 in error detection and correction cache 111 in response to a request for word group (e.g., 131 b) that is not associated with error detection and correction data 132 a, but has its error detection and correction data (e.g., 132 a) stored in the same row (e.g., row 135 d in FIG. 1E) as error detection and correction data 132 a. Controller 110 may retrieve error detection and correction data 132 a and store a copy 112 in error detection and correction cache 111 as part of a process of populating error detection and correction cache 111. Controller 110 may retrieve error detection and correction data 132 a and store a copy 112 in error detection and correction cache 111 as part of a process of populating error detection and correction cache 111 during otherwise unused access cycles on error detection and correction data channel 120 d.

In response to a request to access the first data word group, the first set of check bits are provided to the controller from the error correction data cache without accessing the error correction data channel to receive the first set of check bits (406). For example, in response to a request to read data channel 120 a in order to receive data word group 131 a from memory device 130 a, controller 110 may query error detection and correction cache 111 to determine if a cached copy 112 of error detection and correction data 132 a associated with data word group 131 a is stored in error detection and correction cache 111. If a cached copy 112 of the error detection and correction data 132 a (which is associated with data word group 131 a) is present in error detection and correction cache 111, controller 110 may forego accessing error detection and correction memory channel 130 d. Instead, controller 110 may retrieve the cached copy 112 of error detection and correction data 132 a (without concurrently accessing error detection and correction data channel 120 d and/or error detection and correction memory device 130 d) and use this copy 112 to detect and/or correct errors in data word group 131 a.

FIG. 5 is a flowchart illustrating a method of accessing error detection and correction information from an open row. The steps illustrated in FIG. 5 may be performed by controller 110 and/or one or more elements of systems 100-105. By a controller, a row of a memory device on an error correction data channel is opened (502). For example, in response to a request to access a data word group, controller 110 may open row 134 d of error detection and correction memory device 130 d. Row 134 d of error detection and correction memory device may store error detection and correction data (e.g., error detection and correction data 132 a, 132 b) for data word groups (e.g., data word groups 131 a and 131 b) that are stored in corresponding rows (i.e., have the same row address) of data memory devices 130 a-130 c.

By the controller, a first memory channel of a plurality of independent memory channels is accessed to receive a first data word group that is stored contiguously in a first row of a first memory device coupled to the first memory channel where the first row corresponds to the row of the memory device on the error correction data channel (504). For example, controller 110 may access data memory channel 120 a in order to receive data word group 131 a, which is stored contiguously in row 134 a, where error detection and correction data 132 a for data word group 131 a is stored in row 134 d—which has the same row address as data row 134 a.

By the controller, a first set of check bits associated with the first data word group are received from the open row of the memory device on the error correction data channel (506). For example, error detection and correction data 132 a which is associated with data word group 131 a may be received by controller 110 via error detection and correction data channel 120 d.

By the controller, a second memory channel of a plurality of independent memory channels is accessed to receive a second data word group that is stored contiguously in a second row of a second memory device coupled to the second memory channel where the second row corresponds to the row of the memory device on the error correction data channel (508). For example, controller 110 may access data memory channel 120 b in order to receive data word group 131 b, which is stored contiguously in row 134 b, where error detection and correction data 132 b for data word group 131 b is stored in row 134 d—which has the same row address as data rows 134 a and 134 b.

By the controller, a second set of check bits associated with the second data word group are received from the open row of the memory device on the error correction data channel (510). For example, error detection and correction data 132 b which is associated with data word group 131 b may be received by controller 110 via error detection and correction data channel 120 d.

FIG. 6 is a flowchart illustrating another method of accessing error detection and correction information from an open row. The steps illustrated in FIG. 6 may be performed by controller 110 and/or one or more elements of systems 100-105. By a controller, a row of a memory device on an error correction data channel is opened (602). For example, in response to a request to access a data word group, controller 110 may open row 135 d of error detection and correction memory device 130 d. Row 135 d of error detection and correction memory device may store error detection and correction data (e.g., error detection and correction data 132 a, 132 b) for data word groups (e.g., data word groups 131 a and 131 b). Whether row 135 d of error detection and correction memory device may store error detection and correction data (e.g., error detection and correction data 132 a, 132 b) for particular data word groups (e.g., data word groups 131 a and 131 b) depends on the configuration of controller 110.

By the controller, a first memory channel of a plurality of independent memory channels is accessed to receive a first data word group that is stored contiguously in a first row of a first memory device coupled to the first memory channel (604). For example, controller 110 may access data memory channel 120 a in order to receive data word group 131 a which is stored contiguously in row 135 a.

By the controller, a first set of check bits associated with the first data word group are received from the open row of the memory device on the error correction data channel (606). For example, error detection and correction data 132 a, which is associated with data word group 131 a, may be received by controller 110 via error detection and correction data channel 120 d.

By the controller, a second memory channel of a plurality of independent memory channels is accessed to receive a second data word group that is stored contiguously in a second row of a second memory device coupled to the second memory channel (608). For example, controller 110 may access data memory channel 120 b in order to receive data word group 131 b, which is stored contiguously in row 135 b.

By the controller, a second set of check bits associated with the second data word group are received from the open row of the memory device on the error correction data channel (610). For example, error detection and correction data 132 b which is associated with data word group 131 b may be received by controller 110 via error detection and correction data channel 120 d.

The methods, systems and devices described above may be implemented in computer systems, or stored by computer systems. The methods described above may also be stored on a non-transitory computer readable medium. Devices, circuits, and systems described herein may be implemented using computer-aided design tools available in the art, and embodied by computer-readable files containing software descriptions of such circuits. This includes, but is not limited to one or more elements of systems 100-105, controller 110, and their components. These software descriptions may be: behavioral, register transfer, logic component, transistor, and layout geometry-level descriptions. Moreover, the software descriptions may be stored on storage media or communicated by carrier waves.

Data formats in which such descriptions may be implemented include, but are not limited to: formats supporting behavioral languages like C, formats supporting register transfer level (RTL) languages like Verilog and VHDL, formats supporting geometry description languages (such as GDSII, GDSIII, GDSIV, CIF, and MEBES), and other suitable formats and languages. Moreover, data transfers of such files on machine-readable media may be done electronically over the diverse media on the Internet or, for example, via email. Note that physical files may be implemented on machine-readable media such as: 4 mm magnetic tape, 8 mm magnetic tape, 3½ inch floppy media, CDs, DVDs, and so on.

FIG. 7 is a block diagram illustrating one embodiment of a processing system 700 for including, processing, or generating, a representation of a circuit component 720. Processing system 700 includes one or more processors 702, a memory 704, and one or more communications devices 706. Processors 702, memory 704, and communications devices 706 communicate using any suitable type, number, and/or configuration of wired and/or wireless connections 708.

Processors 702 execute instructions of one or more processes 712 stored in a memory 704 to process and/or generate circuit component 720 responsive to user inputs 714 and parameters 716. Processes 712 may be any suitable electronic design automation (EDA) tool or portion thereof used to design, simulate, analyze, and/or verify electronic circuitry and/or generate photomasks for electronic circuitry. Representation 720 includes data that describes all or portions of systems 100-105, controller 110, and their components, as shown in the Figures.

Representation 720 may include one or more of behavioral, register transfer, logic component, transistor, and layout geometry-level descriptions. Moreover, representation 720 may be stored on storage media or communicated by carrier waves.

Data formats in which representation 720 may be implemented include, but are not limited to: formats supporting behavioral languages like C, formats supporting register transfer level (RTL) languages like Verilog and VHDL, formats supporting geometry description languages (such as GDSII, GDSIII, GDSIV, CIF, and MEBES), and other suitable formats and languages. Moreover, data transfers of such files on machine-readable media may be done electronically over the diverse media on the Internet or, for example, via email

User inputs 714 may comprise input parameters from a keyboard, mouse, voice recognition interface, microphone and speakers, graphical display, touch screen, or other type of user interface device. This user interface may be distributed among multiple interface devices. Parameters 716 may include specifications and/or characteristics that are input to help define representation 720. For example, parameters 716 may include information that defines device types (e.g., NFET, PFET, etc.), topology (e.g., block diagrams, circuit descriptions, schematics, etc.), and/or device descriptions (e.g., device properties, device dimensions, power supply voltages, simulation temperatures, simulation models, etc.).

Memory 704 includes any suitable type, number, and/or configuration of non-transitory computer-readable storage media that stores processes 712, user inputs 714, parameters 716, and circuit component 720.

Communications devices 706 include any suitable type, number, and/or configuration of wired and/or wireless devices that transmit information from processing system 700 to another processing or storage system (not shown) and/or receive information from another processing or storage system (not shown). For example, communications devices 706 may transmit circuit component 720 to another system. Communications devices 706 may receive processes 712, user inputs 714, parameters 716, and/or circuit component 720 and cause processes 712, user inputs 714, parameters 716, and/or circuit component 720 to be stored in memory 704.

The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art. 

What is claimed is:
 1. A memory system, comprising: a plurality of memory channels that each include a respective memory access interface that is to operate independently of the accesses that occur via the other of the plurality of memory channels, the plurality of memory channels including a first data channel to access a first data word group that is stored contiguously in a first row, the plurality of memory channels including an error detection and correction data channel, separate from the first data channel, to access a first group of check bits associated with the first data word group; and, an error detection and correction data cache to, before accessing the error correction data channel to receive the first set of check bits, determine whether the error detection and correction data cache holds a copy of the first set of check bits.
 2. The memory system of claim 1, wherein the plurality of memory channels each include command, address, and data transfer functions that operate independently of the command, address, and data transfer functions of the other of the plurality of memory channels.
 3. The memory system of claim 2, wherein, the error detection and correction data cache determines the error detection and correction data cache holds a copy of the first set of check bits.
 4. The memory system of claim 3, wherein, in response to the error detection and correction data cache determining the error detection and correction data cache holds a copy of the first set of check bits, the error detection and correction data cache is to provide the first set of check bits without concurrently accessing the error correction and detection data channel to receive the first set of check bits.
 5. The memory system of claim 1, wherein the plurality of memory channels includes a second data channel to access a second data word group that is stored contiguously in a second row, the first row to be accessed using a first row address on the first data channel, and the second row to be accessed using the first row address on the second data channel.
 6. The memory system of claim 5, wherein a second group of check bits associated with the second data word group and the first group of check bits associated with the first data word group are stored in a third row that is accessed via the error detection and correction data channel.
 7. The memory system of claim 5, wherein the first group of check bits associated with the first data word group is stored in a third row that is accessed via the error detection data channel and a second group of check bits associated with the second data word group is stored in a fourth row that is accessed via the error detection and correction data channel.
 8. A memory system, comprising: a plurality of memory channels that each include a respective memory access interface that is to be accessed independently of the accesses via the other memory channels, the plurality of memory channels including an error detection and correction data channel to access a first group of check bits corresponding to data stored in a single row of a first memory device accessed via a first one of the other memory channels; and, an error detection and correction data cache to, before accessing the error correction data channel to receive the first group of check bits, determine whether the error detection and correction data cache holds a copy of the first group of check bits.
 9. The memory system of claim 8, wherein the first group of check bits is stored in a single row of an error detection and correction channel memory device that is accessed via the error detection data channel.
 10. The memory system of claim 9, wherein a second group of check bits, stored in the single row of the error detection and correction channel memory device, corresponds to a single row of a second memory device that is accessed via a second one of the other memory channels that is a second member of the proper subset of the plurality of memory channels.
 11. The memory system of claim 10, wherein the first group of check bits and the second group of check bits are to be accessed from the single row of the error detection and correction channel memory device using a single row activate command to access both the first group of check bits and the second group of check bits.
 12. The memory system of claim 8, wherein, the error detection and correction data cache determines that the error detection and correction data cache holds a copy of the first group of check bits.
 13. The memory system of claim 11, wherein the plurality of memory channels are controlled by a memory controller that includes the error detection and correction data cache.
 14. A method of operating a memory system, comprising: accessing a plurality of memory channels each including command, address, and data transfer functions that operate independently of the command, address, and data transfer functions of the other of the plurality of memory channels; accessing a first memory channel of the plurality of memory channels to receive a first data word group that is stored contiguously in a first row of a first memory device coupled to a first memory channel of the plurality of memory channels; accessing, concurrently with the accessing the first memory channel, an error detection and correction data channel to receive a first set of check bits associated with the first data word group; and, before accessing the error correction data channel to receive the first set of check bits, determining whether an error detection and correction data cache holds a copy of the first set of check bits.
 15. The method of claim 14, further comprising: in response to determining that the error detection and correction data cache holds a copy of the first set of check bits, providing the first set of check bits from the error detection and correction data cache without concurrently accessing the error correction and detection data channel to receive the first set of check bits.
 16. The method of claim 14, wherein when the error detection and correction data channel is accessed concurrently with the first memory channel, the error detection and correction data channel is to receive a second set of check bits associated with a second data word group.
 17. The method of claim 16, wherein the second data word group is copied into an error detection and correction data cache.
 18. The method of claim 17, further comprising: receiving a request to access a second memory channel of the plurality of memory channels to receive the second data word group, the second data word group being stored contiguously in a second row of a second memory device coupled to the second memory channel; and, in response to the request to access the second data word group, providing the second set of check bits from the error detection and correction data cache without concurrently accessing the error correction and detection data channel to receive the second set of check bits. 